Water/acid/base/buffers Flashcards
A buffer is a mixture of what? Why is it important in the body?
a weak acid + conjugate base; it prevents large pH changes from happening
WHen is buffering capacity the greatesrt? This is when what is also happening? An effective buttering range is
When acid and conj base amounts are equal; pH = pKa; +- 1 of the pka = pH
What base would a metabolic process generate?
ammonia
Complete oxidation of biological fuels makes __. This can combine with water to make ___.
carbon dioxide. carbonic acid
Carboxylic acids have a pka value in the range of ____-___. A deprotonated ver would have __ charge.
2-4. you assume this if not given a specific value; negative
Aspirin with a pka of 3.5 has to be uncharged. Will aspirin be better absorbed in stomach ph1 or SI ph 8.
the answer is ph1 bc its protonated (ph < pka) and that’s a net 0 charge!
For things to cross the membrane, what is chargign like?
need transporter OR be uncharged or nonpolar
In an exam, can see orotic acid and orotate as the same molecule, true or false?
true! don’t ask!
What does carboxylate/carboxylic acid look like?
R group + COOH
A tertiary amine would have…
three R groups and a H on the Nitrogen (NH)
The pKa value for amines/ammonium ion is ? A protonoated/acidic one has a __ charge.
near 9; POSITIVE
The net charge of a molecule depends on the functional group that dominates, true or false?
FALSE- figure out the charge for each group separately and then add them together.
C=O-NH is what functional group. Is it ionizable?
Amide; nope! don’t worry about it this functional group.
A drug sometimes injected as a local anesthetic has an ionizable amino
group. It is otherwise hydrophobic and enters cells by free diffusion
through the non-polar cell membrane. Once inside the cell, the ionized
form of the drug acts by binding to the intracellular domain of an ion
channel. A localized infection decreased interstitial pH around the site of
injection from 7.4 to 6.8. Which of the following correctly describes a
possible consequence of the decreased pH?
A. It would have no effect on uptake or binding of the drug.
B. It would decrease uptake of the drug.
C. It would decrease binding to the intracellular ion channel.
D. It would increase uptake of the drug into cells, but not
binding to the ion channel.
E. It would increase uptake of the drug and its binding to the
ion channel.
Let’s Try It!
This drug does not like water (nonpolar, hydrophobic butttt…It has amino group that has a pka of 9, so pH is still less than pka, which means its protonated and has a plus one charge so ir will be even harder to cross the membrane (B). ion channel is still nonpolar so it prob wouldnt like the charge? ask why its significant enough to not be A. this problem is equil reaction..
Give a few examples of carboxylic aids in metabolic intermediates
lactic acid, acetoacetic acid, and beta hydroxybutyric acid
